Measuring telomerase activity in various human tumors in routine histology and cytology.

The aim of this study was to investigate telomerase reactivation, to quantitatively measure the human telomerase reverse transcriptase (hTERT) content and telomerase activity level (TA) in routine histological and cytological samples, and to examine the relationship between these values and morphological factors. We analyzed 86 (35 cytological and 51 histological) lesions which were divided into four main groups: renal tumors, soft tissue tumors, bladder-urine and thyroid gland lesions. The relative expression of mRNA of hTERT was examined by real-time polymerase chain reaction (RT-PCR). Almost all of the renal cell carcinomas showed TA. In soft tissue tumors no correlation was seen between TA and histogenesis, aggressiveness and prognosis. Concerning cytological material a very good correlation was seen between TA and the benign or malignant nature of these tumors (92.3% specificity and 60% sensitivity). Our results indicated that TA can be used beside histology also in cytologic samples, for example in the preoperative differential diagnosis of the thyroid gland lesions and urine samples. Telomerase reactivation may not play an important role in tumorigenesis in STT. Useful observations can be made by concentrating not only on one group of diseases or localization but the unselected analysis of routine diagnostic cases can also be of help both in diagnosis and therapy.